The present invention relates to an external Serial Advanced Technology Attachment-based (external SATA-based) flash memory device. More particularly, the present invention relates to a connector-powered flash memory device that can be connected to a host using the SATA protocol signals.
External flash memory devices have been in use for some time. Generally speaking, a flash memory device employs semiconductor memory instead of a magnetic or optical disk to store data. Well known advantages offered by flash memory include higher performance, enhanced background erasing, buffering, and caching for I/O. Furthermore, flash memory has a high degree of reliability, requires lower power and in general involves less size and weight. Compared to magnetic-based or optical-based memory, flash memory is thought to offer better longevity through bad block management techniques, ECC (Error Correction Code), and wear leveling. Furthermore, flash memory is more suitable for use in rugged environments where exposure to shock, high heat, and/or humidity may be expected. Additionally, flash memory is thought to have a greater future since the density of flash memory has been increasing at a higher rate than the rate of increase in the storage density of magnetic or optical-based memory. Although memory devices may employ any type of semiconductor memory, flash memory devices based NAND gates has been particularly popular.
An external flash memory device typically connects to a host using a connector, such as a Universal Serial Bus (USB) connector and a corresponding protocol. The USB protocol comes in a slower-speed version 1.1 and a higher speed version 2.0 and has been widely employed as an interface between a host and an external flash memory device. While the USB protocol is useful as protocol for transferring data to and from external memory devices, the limited top transfer rate of the USB protocol (roughly 480 Mbits/sec) has become a bottleneck in some situations due to simplex situation and the sharing of bandwidth by multiple USB devices. This bottleneck is exacerbated as flash memory read/write throughput increases.
What is desired, therefore, is an external flash memory device that employs an interface protocol operating at a higher data transfer speed than the transfer speed offered by the USB protocol. The alternative higher speed external flash memory device preferably leverages on an existing high speed protocol specification, while providing backward compatibility.